Control system



W. A. DERR CONTROL SYSTEM Dec. 2, 1941.

Filed Aug. 29

' AT ORNEY Patentecl Dec. 2, 1941 Westinghouse Electric & Manufacturing Company, East" lPittsburgh, 'Pa.," a Acorporation of Pennsylvania Application August 29, 1940, serial No. 354,691

(o1: rvs-2) 12 Claims. l

My invention relates, generally, tol control systems, and more particularly-to supervisory control .systems operated in conjunction with tele- -phone systems.

In. the operation of power systems andother systems'havingremotely disposed stations Vit is customaryv toi interconnect the. stations 'with Aa 'telephone system. It is also well knowriinl the operation of systems having remotely disposed `stations to Vcontrol andsupervise-appar'atus atl the remotely disposed stations from a control station. The telephone-systems which interconnect such "remotely disposed `stations usually employringuing currents of frequencies of' from 16to 60 cyclesperrsecond andv the range of voice frequencies transmitted by the telephone system eX- tends upward to above 5000 cycles per second.

-The supervisory control systems usually operate' -1 by: direct current pulsing, the frequency of the pulses being approximately 6 per second.

An object of my invention is to provide a combined telephone system `and supervisory control system which shall function to provide both telemunication channel extending between remotely disposed stations without interference of either of the functions' with the other.

Another object of the invention is to provide a supervisory control *system which `shall function to perform supervisory'control' operations between one stationA and adjacent stations over' a telephone channel which interconnects `the useveral stations without interference of either of the communication functions with 'the other.

These and other objects and advantages will be apparent from the following detailed descrip- 'phone communication and lsupervisory control foperations simultaneously over aV singlecomf tion taken in connection with the vaccompanying Y drawing, in which:

Figure 1 is a diagrammatic representationof a combined telephone and 'supervisory control system embodying the principal features of 'my invention; and

Fig. 2 is a diagrammatic representationof a combined telephone and supervisory control system in which the supervisory control system operates between one station and the two ad- `jacent stations on a telephone system.

In practicing the embodiment of the invention shown'in Fig. 1, insulating transformers 2 andl 4 are connected in the telephone channelv atl stations A and -B betweenwhich it is-desired -to transmit supervisory vvcontrol impulses. supervisory control set of equipment vis `connected*in 155 circuit with' the :line wires and the connected 'transformer windings at each of the stations through i'llter circuits 6 ,and 8, the filter ycircuits being designedto offer high impedance to voice `^and ringing-*currents and lou/impedance to low requencysup'ervisory control pulsing currents.

'A set of utelephone equipment may be connected -at 'anypoint on the line between stations-A and -Bv as shown at station -C .and telephone sets' may be .connected similarly at stations A land B.

inthe embodiment of Fig. 2, supervisory con- 'trol'is'provided between a station F and the adjacent vstations D .and H *and telephone sets may 4-lce provided at any of thest'ations D, E, F, G

Consideringthe system morein detail, the sectionfof the telephone circuit extending between station 'A and station4 B comprising the conductors-"lil and l2 issectionalized or segregated from the remainder of the telephone. circuit Vcornf'prising. conductors I4' and I6 and conductors i8 and 20Abyinsulating transformers 2 and L "I'heiwinding of the transformer 2 at station A,

25 'which is connected to the 'conductors ill-and I2,

is divided into two substantially equal parts 22 and 24, and 'capacitors 26 and 28 arev connected f inf series circuit relation between thewindings 22' and 24. The corresponding winding ofthe -transformer 4- at stationV B is similarly divided 'and has similar capacitorsv associated with the -divided winding, as indicated. Thus the telephone circuitl extending between stations A and vB f includesthe rdivided trans-former 'windings at `the two stations; the 'capacitors at the two sta- Ytionsfand the'line conductors l0 and l2 connect- 'Sing #the two stations.

- set' of supervisory control equipment is pro- 'fv-ided at le'a'chof the' stations' A and B. These .sets fof-supervisory' control equipment' may be such cooperating sets of equipment as areA shown and vfully describedV Yin the patent to Boswau No.

32,091,301, issued'Angust 31, 1937, or any suitable sets of' vcooperating supervisory control equipment operating over a pairV of :line conductors by means` of 'coded impulseshaving a frequency sub- :stanti'ally` less than the frequencyof ringing and ytalking currents in-V a telephone communication system. The -supervisory .control 'equipment at :the station A is connectedbetween the winding-s -22 and24of the transformer 2 ina `circuitwliich extends from one side ofthe winding 24 through -a conductor 30,'a winding 32 of Van inductor'- 3.3, a conductor 1'34,MthesupervisoryA control equipment, lalconductor''36,l a winding 38 of the inductor 33, and a conductor 40 to the transformer winding 22.

A pair of capacitors 42 and 44 is connected in series circuit between the 4conductors 34 and 36. A ground connection is provided for the connection between the pairs of capacitors 26 and 28 and 42 and 44, as indicated.

The connections between the supervisory control equipment at station B and the transformer 4 are identical with those at station A, as indicated in the drawing. The inductor 33 comprising the inductor coils 32 and 38 disposed on a common core is so designed as to offer high impedance to currents of the frequency normally used for ringing in a telephone communication system and voice frequency currents so that these telephone ringing and talking currents will not affect the supervisory control equipment. The condensers 26 and 28 act as a by-pass or shunting circuit for the ringing and voice frequency currents to further prevent the ringing and voice frequency currents from affecting the supervisory control equipment. The capacitors 42 and 44 also provide a shunting circuit for any ringing and voice currents that might be conducted through the windings of the inductor 33.

In the operation of the telephone system, telephone sets of equipment may be connected at stations A and B as indicated at station A directly across the telephone line conductors at any point in the telephone communication system, and the telephone system will operate through the section of telephone circuits between the stations A and B without affecting the supervisory control equipment at stations A and B, by virtue of the fact that the filter circuits 6 and 8 at stations A and B, respectively, will prevent the telephone ringing and talking currents from affecting the supervisory control equipment. When the supervisory control equipment is operated, coded impulses are transmitted between stations A and B over the line conductors l0 and I2, and these coded impulses are of such a low frequency and build up and die down so slowly that they will not be heard in the telephone i" equipment.

. If it is desired to connect a set of telephone equipment to the section of telephone circuit exing and voice frequencies but prevents the drainage of supervisory control current through the telephone equipment, particularly in supervisory control systems where the line conductors are maintained energized and the coding impulses are produced by opening and closing the lineI circuit. The insulating transformers 2 and 4 serve the purpose of insulating the supervisory control section of line from the other telephone equipment in the system.

The capacitors 42 and 44 and 26 and 2'8, in addition to serving the purpose of by-passing the ringing and voice frequency currents and thus preventing them from entering the supervisory control equipment, also serve to prevent the line relays of the supervisory control equipment from releasing too quickly after the break of the coding impulses due to the residual magnetism in the inductor 33 by maintaining a potential on the line opposite to the potential induced in the inductor 33 when the line circuit is broken at the break portion of the coding impulse.

The inductor 33 has its windings 32 and 38 so arranged as to permit passage of extraneously induced currents in the lines Ill and l2, such as might be produced by adjacent power lines or lightning surges to pass frequently to the ground connection between the capacitors 42 and 44. The ground connection between the capacitors 26 and 28 serves the similar purpose of draining extraneously induced currents from the line conductors I8 and I2. The inductor windings 32 and 38, however, are so related as to offer high impedance to the telephone ringing and voice frequencies.

In the embodiment of the invention shown in Fig. 2, apparatus is provided for utilizing the sections of telephone circuit adjacent to a station F for supervisory control operations between the station F and .stations D and H. It will be seen that the telephone equipment at station F is separated from the adjacent supervisory control sections of the telephone circuit by insulating transformers, and that each ofthe other ends of the supervisory control sections are connected to the telephone circuit through insulating transformers. The supervisory control equipment and telephone equipment at each of the stations and the telephone equipment at intermediate stations such as station E and station G may be the same as corresponding apparatus at the corresponding stations in the system shown in Fig. 1. In the system shown in Fig. 2, it will be seen that the station F may be the control station or dispatchers station, and stations D andH may be remote stations controlled and supervised from the station F.

Thus it will be seen that I have provided a combined telephone communication system and supervisory control system which functions to provide both telephone communication and supervisory control operations simultaneously over a single communication channel extending between remotely disposed stations without interference of either of the functions with the other.

In compliance with the requirements ofthe patent statutes, I have shown and described herein the preferred embodiments of my invention. It is to be understood, however, that the invention is not limited to the precise construction shown and described herein, but is capable of modification by one skilled in the art, the embodiments of the invention shown herein being merely illustrative of the principal features of my invention.

I claim as my invention:

1. In a combined telephone andv supervisory control system, a telephone circuit, means connecting cooperating sets of supervisory control equipment to the conductors of said telephone circuit, and circuit means disposed between each of the supervisory control sets and the telephone circuit for preventing the telephone ringing and talking currents from affecting the supervisory control equipment.

2. In a combined telephone and supervisory control system, a telephone circuit, transformer means for sectionalizing the telephone circuit, means connecting cooperating sets ofsupervisory control equipment to the conductors `,of asectionalized section of the telephone circuit, and circuit means disposed between each of the supervisory control sets'and the telephone circuit for preventing the telephone ringing and talking 'agences 3 currents from: affecting they supervisoryl control equipment. i

3. In a vcombined` telephone and? supervisory control system, a plurality of telephoneY circuit sections, an insulating transformer connected between each end of one of thesections and the adjacent section, means connecting cooperating sets of supervisory control equipmentto. the con,- ductors ofl oney section, and circuit means disposed? between each 'of the supervisory control setsandi the-telephone .circuit section for preventing the telephone ringing and talking currentsv from aiecting the supervisory control equipment.

4. In a combined telephone system and supervisory control system, a telephone circuit, a telephone set connected to the circuit at one station, transformer means connected between the telephone set and each of the first adjacent sections of the telephone circuit, transformer means connected between each of the said first adjacent sections oi the telephone circuit and its next adjacent section, cooperating sets of supervisory control equipment connected to the conductors of each of said rst adjacent sections of the telephone circuit, and means disposed between each of said supervisory control sets and the telephone circuit for preventing the telephone ringing and talking currents from affecting the supervisory control equipment.

5. In a combined telephone and supervisory control system, a telephone circuit connecting a plurality of stations, a telephone set connected to the telephone circuit at each of a plurality of the stations, and a supervisory control system operative between two of the stations comprising transformer means connected between the section of telephone circuit which extends between the two stations and the adjacent sections of telephone circuit, cooperating sets of supervisory control equipment connected to the conductors of the telephone circuit section which extends between the two stations, and means disposed between each set of supervisory control equipment and the telephone circuit for preventing the telephone ringing and talking currents from affecting the supervisory control equipment.

6. In a combined telephone and supervisoryl control system, a, telephone circuit connecting a plurality of stations, a telephone set connected to the telephone circuit at each of a plurality of the stations, transformer means connected between a telephone set at one of the stations and each oi the adjacent sections of the telephone circuit, transformer means at each of two other stations on opposite sides of the said one station connecting the sections of telephone circuit adjacent the one station with the next adjacent section of telephone circuit, and supervisory control systems operative between the one station and the said two other stations comprising cooperating sets of supervisory control equipment connected to the conductors of each of said telephone circuit sections adjacent the said one station, and iilter circuit means for preventing the telephone ringing and talking currents from affecting the supervisory control equipment disposed between each of the supervisory control sets and its associated telephone circuit.

7. In a system for operating a supervisory control system over a telephone circuit, insulating transformers connected between the section of the telephone circuit which it is desired to use for supervisory control purposes and the the adjacent sections, capacitor means associated with each of the said transformers, the

'telephone circuitiof the supervisory controlv section comprising awindingof each of the; trans.-

-formersg the capacitor means, and the telephone trol system over a telephone circuit, insulating transformers connectedV vbetween the section. of

the telephone circuit which itis desired: to use forsupervisorycontrol purposes' and the adjacent sections, a pair of capacitor means associated with each of said transformers, the telephone circuit of the supervisory control section comprising a winding of each of the transformers, the pairs of capacitor means, and the telephone circuit line conductors connected in series circuit relation, means providing a ground connection for the connection between the capacitor means of each pair of capacitor means, a set of supervisory control equipment connected in parallel circuit relation with each pair of capacitor means, and lter circuit means disposed between each of said pair of capacitor means and its associated supervisory control equipment for preventing the telephone currents from alecting the supervisory control equipment.

9. In a system for operating a supervisory control system over a telephone circuit, insulating transformers connected between the section of the telephone circuit which it is desired to use for supervisory control purposes and the adjacent sections, the transformer windings associated with the supervisory control section being divided into two sections, a pair of capacitor means connected in series circuit relation with and between the two sections of each of the divided transformer windings, the telephone circuit of the supervisory control section comprising the divided windings of the transformers, the pairs of capacitor means, and the telephone circuit line conductors connected in series circuit relation, means providing a ground connection for the connection between the capacitor means of each pair of capacitor means, a set of supervisory control equipment connected in parallel circuit relation with each pair of capacitor means, and filter circuit vmeans disposed between each of said pair of capacitor means and its associated supervisory control equipment for preventing the telephone currents from affecting the supervisory control equipment.

10. In a combined telephone and supervisory control system, a telephone circuit, transformer means for sectionalizing the telephone circuit, circuit means connecting cooperating sets of supervisory control equipment to the conductors of a sectionalized section of the telephone circuit, each of said circuit means comprising an inductor of such impedance as to prevent telephone currents from affecting the supervisory control equipment, and capacitor means of such impedance as to readily pass telephone current connected in shunting relation with the circuit connections to each of the supervisory control sets.

11. In a combined telephone and supervisory control system, a telephone circuit, transformer means for sectionalizing the telephone circuit, circuit means connecting cooperating sets of supervisory control equipment to a sectionalized section of the telephone circuit, each of said circuit means comprising inductor mean-s of such impedance as to prevent telephone currents from affecting the supervisory control equipment, and capacitor means connected in shunting relation with the circuit connections to each of the supervisory control sets on each side of said inductor means.

12. In a combined telephone and supervisory control system, a telephone circuit, a transformer connected between each end of a section of the telephone circuit which it is desired to employ for supervisory control purposes and the adjacent section, the windings of the transformers that are associated tion being divided into two separately connectawith the supervisory control secble parts, a set of supervisory. control equipment connected in series circuit between the two parts of the divided transformer windings, an inductor connected in circuit between each of the divided transformer winding parts and the associated supervisory control set, a pair of series connected capacitors connected in shunting relation with the supervisory control set between the inductors and the transformer winding parts, a pair of series connected capacitors connected in shunting relation with the supervisory control set between the inductors and the set, and means providing a ground connection for the connection between the capacitors of each pair of capacitors.

WILLARD A. DERR. 

